DE1768264C3 - Process for the production of hydroxy-alkyl mercaptans - Google Patents

Description

While several processes are known that can be achieved by reacting lower epoxides such as ethylene- »5 oxide and propylene oxide with hydrogen sulfide, the relevant hydroxyalkyl mercaptans in good yields make accessible are the previously known options for the preparation of hydroxyalkyl mercaptans with 8-24 carbon atoms from the 3 »corresponding epoxides, unsatisfactory.

It has now been found that hydroxyalkyl mercaptans having 8 to 24 carbon atoms can be prepared in considerable yields from the corresponding monovalent terminal aliphatic epoxides by reaction with hydrogen sulfide in the presence of strongly basic catalysts if the reaction is carried out in the presence of alkali metal or alkaline earth metal hydroxides, alcoholates, phenolates and tertiary and / or quaternary Oniumbasen in amounts of from 0.01 to 10 weight percent, based on the amount of epoxide used, and in the temperature range between -20 and +40 ⁰ C performs.

Alkali or alkaline earth hydroxides are used as strong bases, Alcoholates, in particular alkali metal alcoholates of lower aliphatic alcohols with 1 to 4 carbon atoms, and phenates, in particular the alkali metal compounds of phenol, are used, as well as tertiary ones and / or quaternary onium bases such as trimethylsulfonium hydroxide, tris (j3-hydroxyethyl) sulfonium hydroxide, Dodecyldimethylsulfonium hydroxide, tetramethylphosphonium hydroxide, in particular quaternary ammonium bases, such as. B. triethylammonium hydroxide, benzyltrimethylammonium hydroxide or the dimethylate of the reaction product formed in methanolic solution of 1 mole of Ν, Ν, Ν ', Ν'-tetramethylhexamethylenediamine with 3 moles of propylene oxide.

The basic catalysts are preferably used in amounts of 0.05 to 7 percent by weight on the amount of epoxy used.

The reaction of the epoxides with hydrogen sulfide is preferably carried out at normal pressure, the hydrogen sulfide being used in almost equimolar amounts, based on the epoxide will.

In the process according to the invention, monovalent, terminal aliphatic are used as starting materials Epoxides with 8 to 24 carbon atoms used. The aliphatic epoxides can be straight-chain or be branched. Examples of this are: 1,2-octene oxide, 1,2-tetracose oxide and 1,2-ethylhexene oxide. Mixtures of different epoxides can also be used. As examples of such Mixtures are epoxidized crack olefins.

The starting materials are obtained by epoxidation of the corresponding unsaturated ones according to processes known from the literature Connections z. B. accessible with peracetic acid.

The presence of a solvent is unnecessary to carry out the reaction. It can however sometimes, for example in the case of a high viscosity of the reaction mixture, it may be advantageous to use solvents to add. Suitable solvents are mainly polar substances, e.g. B. alcohols, such as Methanol, ethanol, propanol, and also ethers such as diethyl ether, dioxane, various types of ethylene glycol ethers. Dimethylformamide and dimethyl sulfoxide can also be used. The amount of solvent to be used can vary within wide limits and for example between 50 and 150 percent by weight, based on the amount of epoxy used.

To carry out the reaction, the epoxide and the catalyst can be initially charged. At the desired Reaction temperature wildly with stirring hydrogen sulfide in the amount as it is the reaction mixture just picks up, initiated. The end of implementation is announced when the Exothermicity and is reached when the reaction mixture no longer absorbs hydrogen sulfide. The reaction time is generally 2-3 hours. During implementation, the The temperature of the reaction mixture must be carefully controlled, as it will result in excessive heating exothermic reaction decreases the yield of hydroxyalkyl mercaptan.

When using a solvent, the procedure described can be modified accordingly that the catalyst is initially introduced in the solvent and the epoxide is introduced at the same time of hydrogen sulfide is added dropwise. After the reaction has ended, the products of the process are isolated in the usual way. This can, for example, after neutralization of the catalyst with dilute Acid and separation of the aqueous phase done by working up by distillation. In the Work-up can also convert higher epoxides, which lead to water-insoluble products be carried out in such a way that the reaction mixture is poured into ice water and the separated Purifies crude product, for example by recrystallization.

The products of the process are obtained in high yields and in a very pure form. You are up Can be used in many ways: In pest control they can be used as insecticides and fungicides be used; they are effective antioxidants for rubber compounds and can also can be used as emulsifiers. Due to their polyfunctionality, they are valuable starting materials for numerous syntheses. Of particular interest are their esterification and etherification products, which, depending on the choice of reactants, act as wetting and dispersing agents in the detergent and textile auxiliaries sector, as plasticizers in plastics processing or as additives to lubricating oils and Lubricants can be used.

example 1

80 ml of methanol were admixed with 3.1 g (6.7 percent by weight of catalyst, based on the epoxide) of benzyltrimethylammonium hydroxide and the solution was saturated with hydrogen sulfide at 25.degree. 46.1 g (0.25 mol) of 1,2-n-dodecene oxide were then added dropwise over the course of 45 minutes, with hydrogen sulfide continuously being introduced in such an amount as the reaction mixture could just absorb and the temperature was reduced to 25 ° C. by cooling was held. The addition of hydrogen sulfide was controlled by a downstream bubble counter. After the addition of the epoxide had ended, the reaction mixture took up hydrogen sulfide for a further hour, a temperature of 25 ° C. still being maintained. The catalyst was then neutralized with dilute sulfuric acid, after the addition of ether the aqueous phase was separated off and the organic phase was worked up by distillation. In * ° a yield of 9O ° / o of theory, based on the epoxide, was added n a fraction boiling at 114 ° C / 0.03 Torr fraction having the refractive ^index! £ = 1.4716, the analytical data of which agreed with the values calculated for 2-hydroxydodecyl mercaptan. The assumed constitution was confirmed by the nuclear magnetic resonance spectrum. The analysis data were:

Calculated:

65,99 »/ oC, 12.00 ¹ H Vo, Vo 7.33 O, 14.68% S;

found:

65.92 »/ 0 C, 12.23% H, 7.65» / 0 O, 14.53% S.

OH number (OH h SH-) calculated: 513.6,

found: 505.7.

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The osmometric molecular weight determination in acetone showed in good agreement with the calculated value 218.4 has a molecular weight of 219.5.

Example 2

46.1 g (0.25 mol) of 1,2-n-dodecene oxide were treated with 3.1 g (6.7 percent by weight, based on the epoxide used) of sodium ethylate and, with stirring, hydrogen sulfide in the amount that the reaction mixture was taking up could, initiated. The uptake of hydrogen sulfide was checked using a 5 <> downstream bubble counter. The temperature was kept at 25 ° C. during the reaction by cooling. The reaction was over after 3 hours. The reaction mixture was worked up as in Example 1. 34.4 g of 2-hydroxydodecyl mercaptan, boiling point 108-110 ° C. / 0.009 Torr, refractive index n ^! i = 1.4712. The yield was thus 63% of theory, based on the epoxide used.

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Example 3

In 100 ml of aqueous ethanol (70%), 5.7 g of barium hydroxide octahydrate (6.7 percent by weight Catalyst, based on epoxide) dissolved. The solution was saturated with hydrogen sulfide at 26 ° C, and then 46.1 g (0.25 mol) of 1,2-n-dodecene oxide were added dropwise over a period of 45 minutes. During the addition of the epoxide, hydrogen sulphide was continuously introduced in the same amount as it was the reaction mixture just started to react, after the addition of epoxide was still Hydrogen sulfide added for 45 minutes. The reaction temperature was over the entire reaction time kept at 26 ° C by cooling. After the completion of the reaction, the reaction mixture became worked up as in Example 1. 2-Hydroxydodecyl mercaptan was obtained in a yield of 87% get the theory. The physical characteristics of the product were: boiling point 114 ° C / 0.03 Torr, Refractive index nf? = 1.4716. The molecular weight found osmometrically in acetone was 219.0 good agreement with the calculated value of 218.4.

Example 4

A solution of 0.51 g (1 percent by weight of catalyst, based on the epoxide) of sodium hydroxide in 80 ml of methanol was ^{saturated at 30 °} C. with hydrogen sulfide. 51.3 g (0.4 mol) of 1,2-octene oxide were added dropwise to this solution in the course of 1 hour, the amount of hydrogen sulfide just being taken up by the reaction mixture being continuously introduced and the temperature being kept at 30.degree. C. by cooling . After the addition of epoxide had ended, the reaction mixture took up hydrogen sulfide for a further 2V2 hours, a temperature of 30 ° C. still being maintained. The reaction mixture was then worked up as in Example 1. The yield of 2-hydroxyoctyl mercaptan was 79% of theory, based on the epoxide used. The product had a boiling point of 80 ° C / 0.15 Torr and the analytical data:

Calculated ... 59.20% C, 11.18% H, 19.76% S; found .... 59.38% C, 11.38% H, 19.32% S.

Example 5

In a manner analogous to Example 4, 67.1 g (0.25 mol) of n-octadecene oxide-1,2 were in the presence of 0.67 g of sodium hydroxide in 80 ml of methanol reacted with hydrogen sulfide. It became 2-hydroxyoctadecyl mercaptan with a melting point of 52-57 ° C in a yield of 67% of theory obtain. After recrystallizing twice from gasoline (b.p. 60-95 ° C.), the product had a Melting point of 56-58 ° C and the analytical values:

Calculated ... 71.45% C, 12.66% H, 10.60% S; found .... 71.40% C, 12.95% H, 10.37% S.

Claims (2)

Patent claims: 1. A process for the preparation of hydroxyalkyl mercaptans having 8 to 24 carbon atoms by reacting monohydric terminal aliphatic epoxides with hydrogen sulfide in the presence of basic catalysts, characterized in that the reaction is carried out in the presence of alkali or alkaline earth metal hydroxides, alcoholates, phenates and tertiary and / or quaternary Onium bases in amounts between 0.01 to 10 percent by weight, based on the amount of epoxy used, and in the temperature range between -20 and +40 ⁰ C carries out. 2. The method according to claim 1, characterized in that the catalyst is a quaternary Ammonium base is used.